| 摘要 |
<p>In a broad aspect, the invention relates to an improved downstop seal for use with a rod-piston actuator of a surface controlled subsurface safety valve, wherein the rod-piston actuator has a beveled shoulder formed thereon. The improved downstop seal has a resilient, primary, sealing member having a beveled sealing surface to matingly engage with a portion of the beveled shoulder of the rod-piston actuator; and further has a non-resilient, secondary, sealing member having a beveled sealing surface to matingly engage with a portion of the beveled shoulder of the rod-piston actuator.</p> |
